MouseJoint.java :  » Game » libgdx » com » badlogic » gdx » physics » box2d » joints » Android Open Source

/*
 * Copyright 2010 Mario Zechner (contact@badlogicgames.com), Nathan Sweet (admin@esotericsoftware.com)
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

package com.badlogic.gdx.physics.box2d.joints;

import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Joint;
import com.badlogic.gdx.physics.box2d.World;

/**
 * A mouse joint is used to make a point on a body track a specified world point. This a soft constraint with a maximum force.
 * This allows the constraint to stretch and without applying huge forces. NOTE: this joint is not documented in the manual
 * because it was developed to be used in the testbed. If you want to learn how to use the mouse joint, look at the testbed.
 */
public class MouseJoint extends Joint {
  public MouseJoint (World world, long addr) {
    super(world, addr);
  }

  /**
   * Use this to update the target point.
   */
  public void setTarget (Vector2 target) {
    jniSetTarget(addr, target.x, target.y);
  }

  private native void jniSetTarget (long addr, float x, float y);

  /**
   * Use this to update the target point.
   */
  final float[] tmp = new float[2];
  private final Vector2 target = new Vector2();

  public Vector2 getTarget () {
    jniGetTarget(addr, tmp);
    target.x = tmp[0];
    target.y = tmp[1];
    return target;
  }

  private native void jniGetTarget (long addr, float[] target);

  /**
   * Set/get the maximum force in Newtons.
   */
  public void setMaxForce (float force) {
    jniSetMaxForce(addr, force);
  }

  private native void jniSetMaxForce (long addr, float force);

  /**
   * Set/get the maximum force in Newtons.
   */
  public float getMaxForce () {
    return jniGetMaxForce(addr);
  }

  private native float jniGetMaxForce (long addr);

  /**
   * Set/get the frequency in Hertz.
   */
  public void setFrequency (float hz) {
    jniSetFrequency(addr, hz);
  }

  private native void jniSetFrequency (long addr, float hz);

  /**
   * Set/get the frequency in Hertz.
   */
  public float getFrequency () {
    return jniGetFrequency(addr);
  }

  private native float jniGetFrequency (long addr);

  /**
   * Set/get the damping ratio (dimensionless).
   */
  public void setDampingRatio (float ratio) {
    jniSetDampingRatio(addr, ratio);
  }

  private native void jniSetDampingRatio (long addr, float ratio);

  /**
   * Set/get the damping ratio (dimensionless).
   */
  public float getDampingRatio () {
    return jniGetDampingRatio(addr);
  }

  private native float jniGetDampingRatio (long addr);
}